moving from rds to dynamoDB

Question

have the following fields in RDS

id auto increment
creationDate datetime
status string
reason string
description string
customerID string

there are multiple records for the customerID + creationDate, so I am not able to use creationDate as sort key. The status field combo with customerID won't work as customer can have the duplicate record for same status. If I use the id field I can't auto increment as dynamoDB doesn't allow that? What are my options here? How should my ddb table look like?

Answer 1

The key to DynamoDB is knowing your access patterns. You haven't stated how you plan to query the data, so I can't advise on the overall design, but here is what you can do in order to have a unique primary key.

Do you really need auto-incrementing IDs? If not, consider using a UUID for all new data. Then you could use the ID field as the partition key; you could also use customerId as the partition key and id as the sort key.

If you must have auto-incrementing IDs, then you should store your creationDate in DynamoDB as an ISO 8061 string. Then, you can append a random UUID to the end of creationDate to avoid key collisions. This will allow you to use customerId and creationDate as the primary keys, and you are still able to query using the date (but instead of checking for equality, you should use the begins_with function).

Finally, you can introduce a new field specifically to ensure uniqueness. You could call it simply rangeKey, and it would be a randomly generated UUID that you could use with any other field as the partition key. You can still have your sequential ID field (and create a GSI for querying it, if you want).

I've presented 3 solutions, but they are really all the same—find a way to add a UUID to your primary key.